George Zimmerman, the neighbourhood watch chief who killed black teenager
Trayvon Martin, is expected to be charged over his death, according to
reports.

Prosecutors are expected to announce that the former security guard would be arrested six weeks after police in Sanford, Florida, allowed him to walk free, leading to outrage across America.

He cannot be charged with first degree murder after State Attorney Angela Corey this week cancelled a Grand Jury hearing which is required for such cases, but could face a lesser charges of second degree murder, manslaughter, non-intentional killing or aggravated assault.

The case has shone a spotlight on race relations in the United States, with protesters claiming that the case would have been handled differently had Trayvon been white.

It also raised questions over Florida's controversial "shoot first" self-defence law, called Stand Your Ground, which allows citizens to attack if they believe they are in danger. Zimmerman, whose father is white and mother Hispanic, said he killed the 17-year-old while in fear for his life after Trayvon assaulted him.

Speaking shortly before the news broke that charges were imminent, the teenager's parents addressed the National Action Network, headed by civil rights campaigner Al Sharpton.

His mother, Sybrina Fulton, said: "For the last 44 days, it has been a nightmare, and this is talking from the mother's perspective. I know beyond a shadow of a doubt that justice will be served.

Trayvon's father Tracy added: "As a parent that loses a child, it is very tough to maintain your sanity.

"But I told myself the second day that Trayvon was dead that I would find it within myself to do right by him, to make sure that his death wouldn't be in vain."

Trayvon was killed on February 26 as he walked back from a grocery store where he had been buying sweets for his younger brother.

Zimmerman, a self-appointed neighbourhood watch coordinator, was patrolling the gated community where he and Trayvon's father lived.

A tape of a call he made to police shows that he claimed that there was a black suspect acting suspiciously in the area. He was ordered by the operator not to follow the man, but apparently did so.

Trayvon's 16-year-old girlfriend, who police failed to speak to before releasing Zimmerman without charge, has said that she was on the phone to him at the time, and that he had said he was being followed and was frightened.

She said she heard the sound of someone challenge then slam into the teenager, before the line went dead.

An emergency call made by a neighbour alarmed by the sound of a struggle was also released – on it, someone can be heard screaming in pain or fear before a shot rings out.

Zimmerman was never arrested and was allowed to leave the Sanford police station within hours of Trayvon's death after telling detectives he fired in self-defence.

In the weeks that followed, protests erupted around the country, with thousands of people taking to the streets wearing "hoodies" – hooded sweatshirts – like Trayvon had on when he was killed, and which apparently made Zimmerman suspicious of him.

As tensions rose, Miss Corey, who is expected to announce the charges against Zimmerman, was appointed to review the case.

A separate investigation is being conducted by the Justice Department into Sanford police, to examine whether racism was involved in the handling of the case.

On Tuesday, Zimmerman's lawyers dropped him as a client, saying that he was no longer in contact with them and was acting erratically.

They suggested that he had left Florida – leading the Martin family to say they feared that he would seek to flee justice.